Pbocess of facing the cutting edges of deilling tools



Reissue cl June 11, 1929.. r v Re. 17,323

UNITED STATES PATENT oFFics RIGHARD' ID. DAVIES, OF HUNTILIGTON PARK,CALIFORNIA, AS SIGNOR, BY: MESNE ASSIGNMENTS, TO 1?. L. 86 M. COMBANY, ACORPORATION, OF CALIFORNIA.

PROCESS OF FACING THE CUTTING EDGES OF DRILLING TOOLS.

No Drawing. Original No. 1,613,942, dated January 11, 1927, Serial No.111,384, filed May 24, 1926.

Application for reissue filed October 1, 1928. Serial No. 309,678.

This invention relates to a process of fachardness of over 8, thatwhether such mateing the cutting edges of drilling tools, and rialiswelded on with an acetylene torch or a 55 refers particularly to aprocess of applying a carbon arc electro, there is an oxidation whichhard cutting edge or face to drilling tools accompanies the Weldingprocess and subemployed in the drilling of oil wells, particustantiallyreduces the'hardness of the finished larly for facing core drills, fishtail bits, disk facing. This oxidation may be eliminated bits and th likand the hardness of the original material 60 In the drilling of oilwells, the drilling bit more nearly preserved through providing afrequently is required to penetrate a formasubstance, particularlycarbon, at the weldtion, part of which is composed of granite or duringthe welding operation. Accordingly, quartz, the hardness of which may beapunder the process of the present invention, I proximately 8, asdetermined by the scratch supply carbon preferably in the form of coke,65 method. The steel composing the body of sin'iult'aneously with thesupply of the hard the bit employed in drilling wells has a hardfacingmaterial to the weld, in a quantity suflfi'ness of only about 4; or 5and accordingly is ficient to prevent oxidation and to such an muchsofter than the formation to be pene extent asto produce a finalhardness of the trated with the result that the bits are submetalinexcess of 8. 70 jected to a very-{rapid rate of wear. It has In myprocess I employ metalswhich do therefore been the practice to face bitsemnot rapidly oxidize under a process of are ployed in the drilling ofoil wells with metals welding, Thus, for example," it has been ofincreased hardness in order to preserve the found practical to employ asthe facing matelife of the cutting edges of said bits. In rial, a metalcontaining over 75 per cent of 75 practice, however, the art hasheretofore not tungsten, preferably approximately 85 to 86 beensuccessful in facing these drilling bits per cent of tungsten.

' 2a with a material of a hardness in excess of I11 connection With theuse of the deoxi that of the granite or quartz which must be dizingmaterial, particularly coke, the metal penetrated by the bits. Thesefacings of hard containing 86 per cent of tungsten may be 80.

material are ordinarily applied to the bits welded upon a cutting bit byelectric welding by a process ofarc welding the material on. apparatusemploying carbon electrodes, and The material has also been placed onwith an produces a facing of a hardnessas high as 9 acetylene torch. Asfar as I am aware, prior or 9.1.

to my invention, these methods .have never Thus, in the preferredprocess of forming g5 produced a cutting face with a hardness suba hardfacing upon a metal body, as for exstantially above 7 even though thematerial ample in facing bits, I employ a rod of metal 3-5 welded to thecutting bits may itself have containing over 75 per cent of tungsten andpossessed a hardness as great as 9. preferably about 85 or 86 per centof tungsten,

It is an object of this invention to devise with approximately 3 to 6per cent of carbon, 9 a simple method of directly applying and andadvance such rod in the welding are as simultaneously alloying materialto a metal required and accompanying the welding opbody to form ahardfacing. eration by continuous supply of powdered It is a further objectof the present invencoke to the welding surface. tion to provide amethod and means of facing" An alternate method of welding embody- 5 thecutting parts of drilling bits with a facing the present invention is bytheemploying of a hardness in excess of that of quartz ment of a rodcontaining itself sufiicient powor granite to the end that the life ofthe cutdered coke to prevent oxidation or .to permit ting edge of thesebits may be'substantially the formation of an alloy facing of thedeincreased; also,'the rate of drilling of the sired hardness. For thispurpose, I employ 100 bits maybe substantially increased, and frira-rodof tungsten'of a composition so that ther, the time and expense consumedin rethere is present from 7 5 per cent and preferbuilding andresharpening the bits may be ably per cent of tungsten,'3to 6 per centsubstantially reduced. of carbon, and around this rod, there is I havediscovered in attempting to face the placed approximately 10 per cent byweight, cutting edge of a bit with a material of a of powdered coke, thepowdered coke being admixed with a binder such, for instance, as sugarsyrup, the rod then being baked prior to its use in the welding process.

The particular feature of the present invention resides in the use ofhigh tungsten welding rods in connection with a supply of a reducingagent, such as coke, in sufficient quantities to prevent-oxidation.Either .of the above two features separately havenot so far been shownto be able to produce a face of the hardness above 8. The use of metalwelding rods containing 86 per cent of tungsten of a hardness of 9.6 to9.7 in a welding process results in the facing of a hardness ofapproximately 7 where the coke or reducing material is omitted. Also theuse of the coke in connection with welding rods containing tungsten ofless than 75'per cent is shown also to. result in the production of 21facing of a hardness of less than 8.

The drilling bits faced in such manner have been found to be adapted topenetrate formations with a rate of wear very markedly lower than thatof the drilling bits heretofore employed for the same purpose. Forexample, with the present forms of 0 re drills, it is found mostuniversally necessary to rebuild the cutting faces with an electrictorch, and reface the same after each core taking operation. A coredrill face in accordance with the pesent invention is found adapted torepeatedly take cores without requiring a rebuilding and reconstructionof the bit after each operation:

This invention is of the full scope set forth in the appended claims.

I claim:

'1. The process of facing bits for drilling wells which compriseswelding to the cutting faces of the bits a hard metal containing over 75per cent of tungsten while co-jointly sup- I plying suflicient carbon toproduce a resultant facing having a hardness in excess of 8.

2. A process of facing well drilling bits which comprises applying withan arc weld a facing metal containing over 75 per cent of tungsten whileco-jointly supplying coke, to the are so as to produce a hard facing onthe bit having a hardness in excess of 8.

3. A process of facing bits which comprises arc welding a hard metal tothe cutting face of the hits, the metal containing over 7 5 per cent oftungsten, while supplying powdered coke a-t a rate sufiicient to producea cutting face having a hardness in excess of 8,

\ 4. A welding rod containing a bar of tungsten metal in which there isat least 75 per cent pure tungsten, the-rod having baked theretopowdered coke.

5. The process of forming a hard metal facing upon a metal bodycomprising heating material of which tungsten is the principal elementon the surface of the body to effect 7 fusion of the tungsten andbonding to the body, the material also containing a quantity of carbon,a' portion of the carbon being burned away during the step of fusion.while the remainder hardens the tungsten.

6. The process of forming a hard metal facing upon a metal bodycomprising heating material of which tungsten is the principal elementon the surface of the body by electrical Welding to effect fusion of thetungsten and bonding to the body, the material also containing aquantity of carbon, a portion of the carbon being burned away during thestep of fusion while the remainder hardens the tungsten, the resultingfacing having a hardness in excess of 8. Y Y v 7. The process offorming'a hard metal facing upon a steel body comprising heatingmaterial containing over tungsten on the surface of thebodyto effectfusionof the tungsten and bonding to the body,the material alsocontaining a quantity of carbon being burned away during the step offusion while the remainder hardens the tungsten,

mainder hardens the tungsten, the resulting facing having a hardness inexcess of 8." 9. A process of forming a hard metal facing upon a steelbody comprising heating material of which tungsten is the principalelement on the surface of the body to effect fusion of the tungsten andbonding to the body, the material also containing in excess of.3% ofcarbon.

10; The process of forming a hard metal facing upon'a metal bodycomprising heating material of which tungsten is the principal elementon the surface of the body to effect -fusion of the tungsten and bondingto the body, the material also containing carbon which hardens thetungsten, the fusion being effected under non-oxi%lzling conditions toprevent oxidation of the ngsten, the resulting facing having a hardnessin excess of 8.

11. The process of forming a hard metal facing upon a metal bodycomprising heating material of which tungsten is the principal elementon. the surface-of theabody to effect fusion of the tungsten and bondingto the body, the material also containing more than 3% of carbon whichhardens the tungsten, the fusion being effected. under nonoxidizingconditions, the resulting facing having a hardness in excess of 8.

RICHARD D. DAVIES;

